Apparatus for excavating tunnels



J. H. GREATHEAD. APPARATUS loR EXGAVATING TUNNBLS, SUBWAYS, ,AND sHAIfTs;

N0. 360,959. Patented Api. 12, 1887t WIL' h l.

N. PETERS. Phlvlilllogmphcr. Wnshiuglon, D. C.

:ma Model.) V2 sheets-sheet 2.

' J. HYGRBATHEAD.

APPARATUS for; EXGAVATING TUNNELS, SUBWAYS, AND. SHAPTS. No'. 360,959. Pa entedApr.-l2, 1887.-

nl nul j um Q Inns/2202, J/mfjealeaal.

UNITED STATES PATENT OFFICE.

JAMES Il. GREATHEAD, OF VESTMINSTER, COUNTY OF MIDDLESEX,

' ENGLAND.

APPARATUS FOR EXCAVATING TUNNELSjSUBWAYS, AND SHAFTS.

SP.FCIl-"ICA'IIOlll forming part of Letters Patent No. 360,959, dated April 12, 1887.

Application tiled August 14, 1586. Serial No. 210,941. (No model.) Patented in England Marcil 29, 1884, No. 5,665.

rninster, in the county of Middlesex, England,

have invented a newand useful Improvement in Apparatus for Excavating Tunnels, Subways, and Shafts, (for which I have obtained a' patent in Great Britain, No. 5,665, dated March 29, 1884,) of which the following is a specification.

My invention relates to apparatus for excavating a tunnel, subway, or shaft which, as the excavation advances, is lined internally, it may be,witl1 metal segments bolted together. For effecting such excavations it has been proposed to apply in front of the completed part of the excavation a shield overlapping like a box-lid the front part of the lining, to displace the material in front of the shield by currents of water directed on it from within the excavation, employing tools for loosening it or a rotating boring-head to cut through rock or Yhard material, and then to advance the shield by forcing it forward by means of screw-jacks or hydraulic presses abutting against the completed lining, to extend the lining by placing" fresh segments within the casing of the shield, and thus to proceed step by step in a horizontal, vertical, or more or less inclined direction, asthe case might be. In excavating in this manner through soil more or less porous nnder a water-way, or through ground in which there is water, the currents directed through the shield, to acton the materialin front of it, are opposed by the pressure due to the height of the external water column, and consequently, in many cases where the excavation is at considerable depth, great power is wastedin giving the currents the necessary force to overcome the external pressure. Again, when water under pressure is present in front of the shield, there are great difficulties in getting access to the boring-tools for the purpose of repairing or replacing them; and when the' shield is advanced the part'of it which overlaps the completed lining-leaves an annular vacuity around the lining which, unless it were filled in, might allow dangerous settlement or disturbance of the lining itself or of the soil through which the excavation Vis made.

My invention relates to arrangements by which these difficulties can be overcome, as I will explain, referring to the accompanying drawings. Figure l is a longitudinal section of part of a tubular tunnel lined with metal, showing arrangements according to my invention for balancing the external water-pressure and dis-v posing ofthe dbris of excavation. a longitudinal section showing a modification of the arrangements in cases where the dbris of excavation can be conveniently disposed of externally. Fig. 2 is a part longitudinal sec tion, and Fig. 3 is an end view, of the arrangement for giving access to repair or replace the toolsv of al boring-head in front of the shield.

Fig. 4 is a `section of the apparatus for injecting material to fill the vacuity around the metal lining.

Referring rst to Fig. l, A is the front of the shield, from which extends backward a cylindrical part or lip, B, which, like the lid of'a box, overlaps and can slide along the metal lining C. In the front plate, A, are provided several spherical joint stuffing-boxes, through which tools a may bepassed to loosen the material in front of the shield. In excavating clay or sandy, gravelly, or loarny ground, boulders often occur which haveto be broken up. In such cases the shield is made with a backwardly-projecting pocket, L, for reception of a boulder which may be broken up by tools L When the boulders are such as cannot easily be broken up, an air-lock, such as will presently be described with reference to Figs. 2 and 8, maybe provided above or behind the pocketL, which in that case would be made Fig. 12l iS with a removable lid or end, so that a boulder could be taken bodily out of the pocket.

D is apipe supplying water to issue through nozzles d, so as to scour out the material in front of the shield, causing a Vbackflow of water and dbris along the pipe E. In order to balance the external pressure acting against the outiiow from the nozzles d, I form a clpsed circuit of the pipes Dand E, including a tank, F, in which the debris is allowed to subside. At any convenient part of the pipe D, I employ a 'helical or other pump, G. to create a current along the pipe D. The water issuing the water or in a barge or floating-vessel, in

by the nozzles d against the material in front i of the shield detaches debris, which returns i along with water by the pipe E, and is delivl ered into the settling-tank F, from the upper l part of which the supply to D is drawn. Thus, l, whatever be the external water-pressure, the power required for effecting circulation in the l closed circuit is only that which is necessary to create the current. A backflow-pipe, II, communicating at its hinder end with the external water, or with a discharge under equivalent pressure, allows the water displaced by the advance of the shield to find its way out without being forced through or disturbing the material through which the shield is advanced. By means of a pipe, P, provided with a valve, D can be put in communication with E, for i scouring outthe latter. The debris and mud deposited in the tank F is from time to time i run out into trucks K, charged with water, through outlets f, provided with valves. Each of the outlets f has a lip projecting down into i the water in the truck, so that on the valve being opened the dbris descends from the l tank F into the truck K below, while water aseends from the truck to take its place in the tank. While this operation is performed, valves e in the pipes D and E arekept closed, i so that the tank is not subject to the external pressure. l

The arrangement shown in Fig. l for removl ing debris into trucks within the tunnel is i more particularly applicable when the exca- Vation has been carried far forward from the shaft.

In order to get the trucks K past or under the spoutsf, the latter may be so constructed that they can be telescopcd sufficiently for the purpose, or a flexible section might be ini serted. In some cases, however, it might be preferable to construct the spouts in two seetions and hinge the latter together.

Vhen only a comparatively short portion of the tunnel lilas been formed, and when it is desired to keep space in the interior free, the arrangement shown in Fig I is adopted. In this case the two pipes Dand E are carried up the shaft It and put in communieatien with the external water, so that the pressure in front of the shield is still balanced, as when the circuit is closed, as above described. rlhe pipe D has a suctionnozzle, S, immersed in the water, and the pipe E has a dischargebranch, T, which is also immersed either in which the dbris becolnes deposited, as shown in Fig. I. Vhen there are tidal or other variations of the water-level, the branch I should bejointed to Ein such a manner as to allow of it accommodating itself to the change of level, its mouth remaining immersed in the water, or being lowered to the water-level, so as to maintain the balance of pressurein the circuit.

In order to allow for the advance of the shield from time to time, the pipes D and E are the lower edge of the partition lll.

' ner be dealt with.

, lining C.

at the parts D and E made telescopic, so that while the shield A is being pushed forward by I the hydraulic or other jacks J, the pipes D and E are telescopieally extended, and then,

their valves being` closed, the telescopic parts can be closed in, and additional lengths can be introduced.

As shown in Figs. 2 and 3, I provide for repairing or replacing the tools of a boringhead, O, when such is used, in the following manner: In front of the shield A, I fix a diaphragm or partition, M, extending down from the upper part nearly to the axis of the tunnel, and I thus form an air-lock which can, when required, be charged with compressed air, expelling the water down to the level of By means of an air-lock communicating by a man-hole with the space between A and M a workman can enter this space. The boring-head O, be-

ling turned so that its arms lie horizontally, as

shown in Fig. 3, is drawn backward and then turned partly round so as to bring one of its arms up into the air-space. as shown in Fig. 2 and by the dotted lines O in Fig. 3. The tools on this arm can then be dealt with by 4 the workman, and by turning the head half round those on the other arm can in like man- In a similar way, by providing an air-lock over the pocket L, access can be got to a boulder or other obstruction that may become lodged there.

rIheletter N in Fig. 2 represents a pipe by which air may be supplied t-o the air-lock between A and M.

It will be seen that when the shield is advanced the baekwardly-extending lip B leaves behind it an annular' vacuity, V, around the In order to fill this vacuity, I provide through several of the segments of the lining C holes fitted with plugs, which can be removed, when required, to permit of connecting, by a screw-union or otherwise, of a pipe from a vessel, U. (Shown in Fig. 4.) This vessel is charged with liquid cement and closed air-tight. Compressed air is then forced into it, and this causes the cement to flow from the vessel U into the vacuity V, where it Sets, thus making a solid filling to the vacuity and covering the lining C with a protecting coat. Instead of using compressed air for discharging the cement from the vessel U, water under pressure may be employed, and in this case it is preferred to use a foating piston to keep the water separate from the cement.

Although I have shown in the drawings al rangements suitable for excavating a horizontal tunnel or subway, obviously those shown in Fig. I would be suitable for a tunnel or subway somewhat inclined, and those shown in Fig. l would be suitable for avertical shaft or for a tunnel or working at a considerable inclination.

Having thus described the nature of my invention and the best way I know of carrying the same into practical effect, I claim- I. In apparatus for excavating tunnels or subways, in combination with a shield capa- ICC ble of being pushedforward as the excavation advances and provided with nozzles by which Water-currents are directed on the material to be excavated, a pump, pipes, and their connections arranged so as to form with the external water a closed circuit, substantially as and for the purpose herein set forth.

2. In apparatus for excavating tunnels, sub# ways, or shafts, in combination with a shield capable of being pushed forward as the excavation advances, and, provided with nozzles by which water-currents are directed on the :material to be excavated, a pump and pipes extending backward, and a settling-tank having outlets which are controlled by valves and dip into water contained in trucks for reception of the settled dbris.

3. In combination with the shield employed in conjunction with a'boring-headin excavating a tunnel, subway, or shaft, a diaphragm or partition, M, and a partition, A, forming an air-lock for giving access to the tools of the boring-head, substantially as described.

4. The combination, with a shield capa-ble of being pushed forward and a lining for a '25 tunnel which follows the advance ofy said shield, of an air-tight vessel containing liquid cement, a pipe extending from the bottom of said vessel through the lining of the tunnel, and a pipe entering said vessel from the top 3o and connectedwith a reservoir of compressed air or Huid under pressure, whereby the cement may be forced into the annular space around the lining, substantially as described.

In testimony whereof Ihavesigned my name 3 5 to this specification, in the presence of two subscribing witnesses, this 8th day of July, A. D. 1886.

. J. H. GREATHEAD. Witnesses:

iClerk to 'Abel Im'ra'y, Consulting Engineers and PatentAgents, 28 SouthamptonBuildings, Lon` don, W C. 

